Door latch



Oct. 12, 1937. w. c. MCWHIRTER DOOR LATCH Filed Jan. 9, 1936 2Sheets-Sheet l INVENTOR y William CMQWZZL'PAQP.

Q/KW [S ATTORNEY W. C. M WHIRTER DOOR LATCH 2 Sheets-Sheet 2 Oct. 12,1937.

Filed Jan. 9, 1956 vi) a w I I I n I I! II E) I I I I I N N} I like I I,I (o I INVENTOR WLllLam CMQWZIIPL QP Q Rum HIS ATTORNEY Patented Oct.12, 1937 Application January 9, 1936, Serial No. 58,338

2 Claims.

My invention relates to door latches, and particularly to door latcheswhich are suitable for latching the doors of pressed steel cabinets andthe like in one or more open positions.

One object of my invention is to provide a door 1atch which willautomatically latch a door in a predetermined open position when it ismoved in one direction to such position but which will permit the doorto remain unlatched when it is moved in the opposite direction past suchopen position.

Another object of my invention is to provide a door latch of the typedescribed which is inexpensive to manufacture and install, and whichwhen installed gives minimum interference with apparatus in the cabinet.

I will describe one form of door latch embodying my invention, and willthen point out the novel features thereof in claims. c

In the accompanying drawings, Fig. 1 is a front elevational view showinga pressed steel cabinet provided with a door latch embodying myinvention, the door being rotated from its closed position and a portionof the cabinet and the door being broken away or removed to betterillustrate the construction of the latch. Fig. 2 is a sectional view ofa portion of the cabinet illustrated in Fig. 1 taken above the doorlatch, the door of the cabinet being shown in its closed position andcertain of the parts being broken away to better illustrate theconstruction of the latch. Fig. 3 is a fragmentary sectional viewsimilar to Fig. 2 showing the door latch embodying my invention on anenlarged.- scale, the parts being shown in full lines in the positionswhich they occupy when the door is rotated from its closed position, andin dot and dash lines in the positions which they occupy when the dooris rotated 90 from its closed position. Fig. 4 is a sectional view takenon the line IVIV of Fig. 3.

Similar reference characters refer to similar parts in each of theseveral views.

Referring to the drawings, a door latch embodying my invention is hereshown applied to the door I of a pressed steel cabinet 2, but it shouldbe particularly pointed out that my invention is of general utility, andmay be used wherever it is found to be advantageous. The door l issecured to the cabinet proper by means of hinges 3, and is free toswingfrom its closed position through an angle of substantially The doorlatch comprises, in general, a bracket 4, a link 5, and a latch plateii. The bracket t is provided with a vertical portion 4 which is weldedto the upper part of the door I in the position shown, and with ahorizontal portion i having an upstanding pin 1 secured thereto as byriveting.

The link 5 is provided at one end with a hole 5 which receives the pin iwith suiiicient clearance to permit the link to move vertically througha short distance, and at the other end with a screw-threaded hole 5which receives the lower end of an upstanding stud 6. The link 5 isretained on the pin i by means of a cotter key 5 which passes through asuitable hole provided in the upper end of the pin above the link.

The stud i3 is locked in an adjusted position in the hole 5 by means ofa jam nut l0, and is provided at its upper end with an enlarged shankportion 3 and with a disk-shaped head 8 As best seen in Fig. 4, theenlarged shank portion 8 is formed with a tapered lower portion 8, andis somewhat smaller in diameter than the head 8*.

The latch plate 6 is secured as by welding to an inwardiy extendingportion of the door jam of the cabinet 2 above the door I, and isprovided with a longitudinally extending slot '3 which slidably receivesthe stud 8 in such mannor that movement of the door will cause the studto move along the slot to different positions. The link 5 and stud 8 arebiased by gravity to a position in which the enlarged shank portion 8 ofthe stud 8 tends to enter the slot 6*, but this slot is made narrowerthan the enlarged shank portion 3 except at two enlarged portions 6 and5 which are formed in the slot at the positions which the stud occupieswhen the door is swung 99 and 170, respectively, from its closedposition, and these enlarged portions of the slot are of such size andshape that the enlarged shank portion of the stud will drop into eitherenlarged portion of the slot when and only when the stud is centrallylocated with respect to such enlarged slot portion. It will be apparentthat when the enlarged shank portion of the stud enters either enlargedportion of the slot, the door I will then be latched in thecorresponding position, and will subsequently remain latched in thisposition until the link and stud are manually raised to remove theenlarged shank portion of the stud from the enlarged portion of theslot.

The door latch also comprises two guides l2 and H which are secured tothe latch plate 6 on opposite sides of the slot 5*, and which cooperatewith the enlarged head 8 of the stud 8 in such manner that when the doorI is moved I from its closed position to either its 90 or 170 openposition the stud will be held in the proper position to cause theenlarged shank portion of the stud to automatically drop into' theenlarged slot portion 6 or 6, as the case may be, but that, when thedoor is moved toward its closed position past its 90 open position, thestud will be permitted to move rearwardly, due to the thrust on the link5, to a position in which the tapered lower end of the enlarged shankportion will ride on the latch plate 6 in such manner that the enlargedshank portion will be prevented from entering the enlarged portion 6* ofthe slot.

It will be-seen, therefore, that with the latch constructed inaccordance with my. invention, when the door I is opened to either its90 position or its 170 position, the door will automatically becomelatched in such position unless the link 5 is manually held in its upperposition, but that, when the door is moved toward its closed positionpast its 90 'open position, the angular disposition of the parts willcause the tapered lower end of the enlarged shank portion of the stud tocooperate with the latch plate at the rear edge of the slot in suchmanner that the enlarged'shank portion of the stud will be preventedfrom dropping to its latching position, with the result that inoperating the door from its full open to its full closed position, nolatching action will result. The position which the parts occupy whenthe door is latched in its 170 posi tion is shown in full lines in Fig.3, and the posi tions which the parts occupy when the door is latched inits 90 open position are shown in full lines in Fig. l and in dot anddash lines in Fig. 3,

while the positions which the parts occupy when the door is closed areshown in Fig. 2.

A stop I3 is secured to the link 5 intermediate its ends, and this stopcooperates with the door at point l in the manner shown in Fig. 3 toprevent the door from being rotated more than 170 from its closedposition.

larged shank portion, a fixed latch plate having It should beparticularly pointed out that while in describing my invention I haveshown the latch constructed in such manner that it' will latch the doorin only two open positions, by providing the slot 6 with additionalenlarged portions similar to the enlarged portions 6 and 6, the doorlatch may be made to latch the door in a plurality of other openpositions as will be readily understood from the foregoing descriptionand from an inspection of the drawings.

Although I' have herein shown and described only one form of door latchembodying my invention, it is understood that various changes and.modifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A door latch comprising a link pivotally attached at one end to thedoor and provided at the other end with an enlarged shank portion andwith a head which is larger than said ena slot which slidably receivessaid stud and which is provided with an enlarged portion at the positionsaid stud occupies when said door is moved to a predetermined openposition .and which is narrower in width than the diameter of saidenlarged shank portion of said stud except at said enlarged portion ofsaid slot, said link and said stud being biased to such positions thatsaid enlarged shank portion of said stud will automatically enter saidenlarged portion of said slot when said two enlarged portions are inaxial alignment, and the parts being so disposed that said stud willtend to remain out of axial alignment with said enlarged portion of saidslot during movement of said door past said predetermined open position,and a guide cooperating with the head of said stud to cause said stud toalign axially with said enlarged portion of said slot when said door ismoved in one direction to said predetermined open position.

2. A door latch comprising a link pivotally attached at one end to thedoor and provided at the other end with an enlarged shank portion havinga tapered lower portion and with a head which is larger than saidenlarged shank portion, a fixed latch plate having a slot which slidablyreceives said stud and provided with an enlarged portion at the positionsaid stud occupies when the door is moved to its full open position andwith another enlarged portion at. the position said stud occupies whenthe door is moved to an intermediate open position, said link and saidstud being biased to such positions that said enlarged shank portion ofsaid stud tends to enter said slot and the parts being so proportionedthat said enlarged shank portion is prevented from entering said slotexcept when said stud is centrally located in one or the other of theenlarged portions of said slot and that said stud will tend to move to aposition in which the tapered lower portion of the enlarged shankportion will ride on the latch plate at one side of the slot when thedoor is moved from its closed toward its open position and at the otherside of the slot when the door is moved from its open toward its closedposition, and two guides secured to said latch plate on opposite sidesof said slot and cooperating with the head of said stud in such mannerthat said stud will be guided to the proper position to enter eitherenlarged portion of the slot when the door is moved from its closedposition to the corresponding open position but that when the door ismoved toward its closed position past its intermediate open positionsaid stud will be permitted to move to the position in which the taperedlower portion of said enlarged shank portion rides on said latch plateat the edge of said slot, whereby the door will become automaticallylatched in its intermediate and full open positions when moved to thesepositions from its closed position but will remain unlatched duringmovement of the door toward its closed position past its intermediateopen position.

WILLIAM C. MCWHIRTER.

